<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>JS-对象-DOM</title>
</head>

<body>
    <img id="h1" src="img/off.gif"> <br><br>

    <div class="cls">传智教育</div> <br>
    <div class="cls">黑马程序员</div> <br>

    <input type="checkbox" name="hobby"> 电影
    <input type="checkbox" name="hobby"> 旅游
    <input type="checkbox" name="hobby"> 游戏
</body>

<script>
   // 1. 点亮灯泡：src 属性值
    var img = document.getElementById('h1');
    img.src = "img/on.gif";


   // 2. 将所有div标签的内容后面加上：very good(红色) <font color='red'></font>
   var divs = document.getElementsByTagName('div');
   for (let i = 0; i < divs.length; i++) {
    const div = divs[i];
    div.innerHTML += "<font color='red'>very good</font>";
   }

   // 3. 使所有的复选框呈现选中状态
   var ins = document.getElementsByName('hobby');
   for (let i = 0; i < ins.length; i++) {
    const check = ins[i];
    check.checked = true; // 选中
   }


</script>

</html>